fix: fix up timestamps

proto/xmtpv4/envelopes/envelopes.proto

@@ -85,19 +85,20 @@ message SafetyFailure {
 }
 
 message UnsignedMisbehaviorReport {
-  // Client time or server time?
-  // Can we query by this time? Is it strictly increasing?
-  uint64 report_time_ns = 1;
+  uint64 reporter_time_ns = 1;
   uint32 misbehaving_node_id = 2;
   Misbehavior type = 3;
   LivenessFailure liveness = 4;
   SafetyFailure safety = 5;
-  // Nodes MUST verify this field is false for client-submitted reports
+  // Nodes must verify this field is false for client-submitted reports
   bool submitted_by_node = 6;
 }
 
 message MisbehaviorReport {
-  bytes unsigned_misbehavior_report = 1;
+  // Server time when the report was stored. Used only for querying reports.
+  // This field is not signed.
+  uint64 server_time_ns = 1;
+  bytes unsigned_misbehavior_report = 2;
   // Signed by the node hosting the report
-  xmtp.identity.associations.RecoverableEcdsaSignature signature = 2;
+  xmtp.identity.associations.RecoverableEcdsaSignature signature = 3;
 }